SPI-1005による一時的な聴覚閾値シフトの防止のための耳保護

The objective of this study was to determine the safety and efficacy of SPI-1005 in the prevention of sensorineural hearing loss or temporary auditory threshold shift (TTS) using pure tone audiometry. Subjects with normal to slight hearing loss were screened on clinic visit day 1 (CV1) and after satisfying specific otologic inclusion and exclusion criteria, were enrolled and randomized to either SPI-1000 (placebo) or one of three doses of ebselen (SPI-1005): 200, 400 or 600 mg. Subjects began taking placebo or SPI-1005 by mouth for four days beginning two days prior to CV2. On CV2 subjects had their blood drawn for peak/trough analysis of ebselen and metabolites and their baseline hearing thresholds determined by audiometry. Subjects were then exposed to 100 decibels (dBA) of sound delivered from a calibrated iPod® via insert earphones for 4 continuous hours. Subjects had their hearing serially tested at 4 additional times post-noise exposure on the same day to determine their threshold shift. Subjects returned to clinic 24 hours later on CV3 and 7 days later on CV4 for additional safety and efficacy assessments including repeat audiometry. Efficacy was determined by comparing the threshold shift in an SPI-1005 treated group vs placebo.

Exposure to SPI-1005 (ebselen and the major and minor metabolites) was quantified from plasma by LC-MS/MS. The plasma values from the peak/trough sampling were taken before and after the 5th oral dose on Clinic Visit 2 (CV2) when subjects were expected to be at steady-state. Plasma selenium levels were quantified by ICP-MS prior to dosing at CV1, at CV2 during peak/trough sampling for ebselen and metabolites, and at CV4 or 5 days after the last scheduled dose.

The multi-dose safety of SPI-1005 was determined by repeated History & Physical examinations, serology (Chemistry Panel-20), hematology (CBC with differential), and radiology (chest x-rays). Safety was determined by comparing the changes in laboratory values in SPI-1005 groups vs placebo.